Weather officials in Japan are warning of more heavy snow this weekend, mainly in coastal areas along the Sea of Japan.

A strong cold air mass brought a record snowfall of about 200 centimeters to mountainous areas in Niigata and neighboring Gunma prefectures from Tuesday to Thursday.

Another blast of heavy snow is expected for coastal areas of the country along the Sea of Japan starting around Friday evening.

Due to a strong cold air mass over the Japanese archipelago, coupled with the season's typical atmospheric air pattern, heavy snow continued falling in mountainous areas from northern through western Japan.

A broad swath of Japan is digging itself out from a massive snowfall. Weather officials are warning of slippery roads - and even avalanches - for areas stretching from Hokkaido down to western Japan.

Residents of a community north of Tokyo spent the morning clearing away a blanket of fresh snow. A record 128 centimeters of the white stuff fell over Minakami Town in a single day.

The season's most powerful cold air mass over Japan is bringing heavy snow to areas on the Sea of Japan coast from Hokkaido in the north and to the Chugoku region in the southwest. Weather officials are calling for caution against avalanches, icy roads, and traffic disruptions.

Snowfall in the 24 hours to Wednesday morning was 128 centimeters in Minakami Town in Gunma Prefecture, and 113 centimeters in Yuzawa Town in Niigata Prefecture -- both the heaviest 24-hour snowfalls on record.

Japan's Defense Ministry says it is considering sea-based alternatives to the Aegis Ashore missile defense system. Earlier this year, the ministry abandoned a plan to deploy the land-based system at two locations.

Defense Minister Kishi Nobuo disclosed the sea-based options at a meeting of ruling Liberal Democratic Party lawmakers on Thursday.

Japan's Foreign Minister has expressed concern over China's advances in the South China Sea at the East Asia Summit with his counterparts.

Toshimitsu Motegi took part in the online meeting held late Wednesday, Japan time. The event was attended by foreign ministers of the 10-member Association of Southeast Asian Nations, as well as Japan, China, the United States, Russia and others.

Weather officials in Japan say the country's sea surface temperatures in August were the highest on record.

The Meteorological Agency says the average water surface temperatures of the Pacific side of eastern and western Japan, as well as the southern islands of Okinawa and Amami, were around 30 degrees Celsius last month.

A Japanese government expert panel has agreed to a plan to reduce the amount of radioactive wastewater stored at the Fukushima Daiichi nuclear plant, by releasing it into the sea or the air.

Water used to cool the molten nuclear fuel from the March 2011 accident is treated to remove most of the radioactive material. But tritium and some other substances are left in the treated water, and the amount stored has reached about 1.2 million tons in almost 1,000 tanks.